Technical Field
The instant disclosure relates to a headphone, and more particularly, to a noise-reducing headphone.
Related Art
Headphones are used to transfer sounds in communication, teaching, and music listening. Headphones have variant structures and types such as full size headphones, in-ear headphones, or earphones. Although general in-ear headphones or full size headphones are capable of reducing noise about 15 db to 25 db, it is not enough if environment noise is loud. When using these headphones, users are hardly hearing sounds of movies or music reproduced by the headphones because of the affections of loud environment noise. A kind of noise-canceling headphones can cancel noise in a manner of destructive interference to neutralize outside noise. A microphone in the noise-canceling headphones is utilized for sensing sound waves of noise transferred from outside into a housing of the headphones. And speakers in the headphones are utilized for accordingly produce pressure waves to neutralize noise. Consequently, users using the noise-canceling headphones have no need to increase the sound volume of the headphones even in the circumstance that environment noise is loud.
By the anti noise control (ANC) means, the noise-canceling headphones can now cancel unpleasant noise coming from outside environment. The noise-canceling headphones include electronic devices and speakers to perform active neutralizing process. The electronic devices include at least one microphone disposed close to the ear of users for receiving outside noise, and an electronic circuit capable of accordingly generating signals of which the phases are inverted relating to the phases of noise. The generated inverted signals can destructively interfere and neutralize outside noise that enter users' ears in the first place.
Noise-canceling headphones available on the markets include a speaker unit, a protective cover, and a microphone hung below the speaker unit or disposed on a periphery of the protective cover of the headphones such that the microphone cannot receive sounds evenly distributed around the speaker unit. As a result, the electronic circuit generates inverted signals merely according to sounds received from a partial area of a periphery of the speaker unit. To improve relative structures of the headphones is therefore desirous.